The present invention relates to wellpoint assemblies and to a method of installing wellpoint assemblies and especially to a system using flexible header pipes which can be unreeled into any desired pattern, aligned and connected to well point assemblies.
It is necessary to dewater a construction area when construction work is being done below the ground surface in order to remove all water and other liquids from an excavation area to provide dry working conditions. The most common technique of dewatering an excavation area is to sink a plurality of well points around the area and connect a pump to each of the well points so that the water will be pumped from the area surrounding the excavation. In a typical wellpoint system, a series of rigid header pipe, such as PVC plastic pipe, is laid around the excavation site and the pipes installed together through clamp-type pipe couplings. The rigid header pipe has holes drilled therein and a coupling attached to the holes in the header pipe so that a wellpoint assembly can be attached to the rigid header pipe. The wellpoint assembly may include a short smaller pipe having a coupling thereto for coupling to the rigid header pipe and to the top of one of the wellpoint well heads. The entire wellpoint system is attached to a dewatering pump to remove water from each of the wellpoint assemblies into the rigid header pipe to maintain the excavation area dry. This type of wellpoint system has worked satisfactory for many years but requires the use of large amounts of rigid pipe which typically may be 20 feet long and various types of coupling mechanisms for coupling the pipe together. When using a typical rigid header pipe system that is to conform with the shape of the excavated area, it is necessary to use various fittings, ells, tees, couplings, clamps and multiple lengths of pipe to custom assemble the header line. Each well point installation is essentially a ring system and the cost of installing and removing the rigid pipe is further complicated by the removal of the system which frequently has little salvage value, except for the pump, for any other well point installation.
The present invention deals with a flexible header pipe which is formed of one continuous piece in any length desired and has couplings already formed therein at spaced points along the flexible header pipe for attaching well point assemblies. The flexible header pipe can be stored and removed from a large reel and shaped to form a wellpoint layout of any desired pattern for attaching the wellpoint assemblies. The header pipe can be easily disconnected and moved without being disassembled. This is especially productive in progressive wellpointing for long utility sewer and force main lines where 50 feet to 100 feet of flexible header can be moved on the ground by hand or mechanical means to its next location without being disassembled and loaded onto a vehicle and then reassembled again for installation. Means must be provided to align the flexible pipe for attaching the wellpoint assembly connecting line which is typically connected to the top of the flexible header. The flexible header might be located in a wide variety of positions as the pipe is laid out into a pattern around an excavation site.
There have been any number of prior wellpoint systems but one system can be seen in our prior U.S. Pat. No. 3,566,982 dated Mar. 2, 1971 for a wellpoint system. Another typical system can be seen in U.S. Pat. No. 4,020,902 and in U.S. Pat. No. 3,995,690 for wellpoint system and in the various references cited in these patents. The aim of the present invention is to overcome the difficulties in setting up, removing and resetting up a wellpoint system by providing a flexible wellpoint header having attached couplings for wellpoint assemblies and means for storing the pipe on a reel and for aligning the pipe for the attachment of the wellpoint assemblies.